Serv-U FTP server includes web, mobile device, SFTP and FTPS file transfer for Windows or Linux. Now also includes "ad hoc" secure file sharing. Used by 9 of Fortune 10. Each server supports 100's of GBs per day and 1000's of users.

FileCOPA takes the hard work out of running an FTP Server. The FileCOPA FTP Server installs on any version of the Microsoft Windows operating system with just a few clicks of the mouse and automatically configures itself for anonymous operation.

Quick 'n Easy FTP Server is a multi threaded FTP server for Windows 98/NT/XP/2003 and Vista(32 bits) that can be easily setup even by inexperienced users. New users can be easily created by a wizard which is guiding you step by step in the process.

Cerberus FTP Server is a full-featured and secure FTP server. It is free for personal, non-business use. Companies can purchase it for $69.95. I have to admit that I haven't used FTP servers for a long time.